My sister has a 2004 Nissan Sentra with a 1.8L engine, and a day or two ago she started noticing some (not a lot) smoke coming from the engine compartment after driving for a long time (i.e., more than 20-30 minutes). The smoke is coming from a component on the front of the engine, which I am fairly certain is the exhaust manifold. Here is a picture of where it is located in the engine compartment (this is not my car, it is just to show the general location):
And here is the best picture I could get of the component itself:
This started happening right after getting an oil change, so I suspect that the guy who did the oil change spilled some oil, and when the engine gets nice and hot it simply burns off that excess oil.
Can anyone confirm whether or not this is the exhaust manifold, and tell me if I should be more worried than I am? Currently I am planning on just letter her drive it for a few days, to see if the problem goes away by itself.